Changes in the heritable attributes of populations of organisms over time. The mechanisms of evolution are mutation, migration, drift, and selection.

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What are constrained genetic elements?

I am somewhat of a newbie in evolutionary biology currently taking my first steps in bioinformatics. I was reading a paper when I came across the term "constrained genetic elements", referring to ...
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93 views

What factors cause males to be more common than females in humans, from an evolutionary perspective? [duplicate]

Fisher's principle states that there should be a 1:1 ratio between males and females born on average for a population. However, if you look at birth statistics your find that boys are slightly more ...
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Evolution of blood types [duplicate]

What are the popular theories regarding how our blood divided into 4 groups. Particularly I'm interested in whether this was originally linked to disease. Thanks for your answers, useful articles and ...
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77 views

Do all mammals have a Ventricular system?

I am familiar with the human Ventricular system that circulates Cerebrospinal fluid. This is needed among other reasons, to suspend the heavy human brain, and for injury protection. Do all mammals ...
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1answer
79 views

term for species that produces males only to mate with mother or sisters

In reading about unique reproductive strategies I've run into two closely related and comparatively unique mechanics. Both involved a female who was born 'pregnant' with at least a male, but the male ...
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Variance in reproductive success and effective population size

Background The effective population size $Ne$ is the size of the Wright-Fisher population that experience the same amount of drift than the population under consideration. The higher the variance in ...
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76 views

What is the evolutionary tradeoff against primates producing multiple offsprings (litter)?

If we evolved to have multiples all the time we would more likely have extended families living together in 1 house. This would be better than the spouses by themselves for multiple reasons including ...
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Why does a coconut have exactly three holes

A theory says: As coconut is a sibling of palm, somehow long time ago, three palms were in a same husk. Based on evolution theory, it's how the coconut was born in the world with three holes. ...
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Which primates can swim underwater?

I saw a documentary awhile back and they were profiling a certain species of monkey which regularly swims underwater. I can't recall which species it was but they said it was rare for primates to do ...
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What makes tones sufficiently useful that it would lead to the evolution of tonal processing?

I will define a "tone" as  a steady periodic sound. As an example, I consider a sinusoidal wave to be a tone. By "tonal processing", I mean ratio relationships between the notes. For instance, if I ...
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39 views

Seeing through the rain

This question leads me to wonder about seeing in and through rain. From visual point of view, rain is light-bending droplets moving downwards, unformly in steady rain, less uniformly if there's ...
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140 views

Evolution of a Population

Scientists observe a newly established population of sexually reproducing plants growing on the shore of a small island. An observable trait of the plant has two possible phenotypes. It is determined ...
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367 views

Hardy-Weinberg Equilibrium Question

I have four questions concerning H-W Equilibrium: (i) In a population of mice, the presence of black spots is the result of a homozygous recessive condition. If the frequency of the allele for this ...
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What is the distribution of the number of heterozygotes in finite populations?

Consider a bi-allelic locus with alleles A and a. We denote the frequency of the A allele by ...
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83 views

Junk DNA and “random” mutations [closed]

I'm somewhat irritated by "mutation" generally being described as a fully random factor in evolution: pure randomness does not seem like something that can survive in a long evolutionary process. And ...
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Why is 2 sexes in an organism so common? [duplicate]

Sorry if this is a super simple question, but why do a lot of species have only 2 sexes? Some species just have 1 sex, but I've never heard of an organism having 3 sexes, for example. 3 sexes seems ...
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3answers
222 views

Why does all life use the same macromolecules in their genetic code?

There is no biochemical constraint of any sort, so why doesn't some other code work? Why is it specifically RNA/DNA?
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How octopus develops its imitation skill?

I've watched one documentary about a Mimic octopus which they can imitate another animals in several form e.g. a Lion fish, a Sea snake, a Flatfish, etc. My question is how these octopuses can have ...
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How did the double circulatory system evolve from the single circulatory system

I already learned how the mammal circulatory system (double circulatory system) evolved from the reptilian circulatory system. How did natural selection evolve the reptilian circulatory system and the ...
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Is it possible there were multiple origins of life? And, if so, why did the one which became the common ancestor between all organisms prevail?

I have learned that all currently-living organisms come from a common ancestor, which I theoretically understand. However, my professor in a class mentioned that there is a chance that there were ...
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Why do we turn darker in the sun? [duplicate]

I tried the all powerful google to answer this question - but I am not getting the answer I seek. I know we turn darker because the skin produces melanin. The question remains - why darker? I am a ...
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1answer
268 views

why didn't natives of south america evolve darker skin?

I understand that darker skin tone is caused by melanin which helps to protect against the extra UV radiation that comes from more direct sunlight. It evolved in Africa before we migrated away from ...
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48 views

How did the tendency to perform death rituals evolve?

Both elephants and humans perform rituals when deaths occur. However, I do not see any evolutionary benefit of this. The rituals take time, which apparently could be better spent hunting, foraging, ...
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3answers
160 views

Why didn't humans evolve to reproduce identical twins all the time?

According to the selfish gene theory, it seems like because identical twins sometimes get produced, a mutation to a gene that says, "if you have an identical twin, be fully altruistic towards them" ...
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How did zootoxins evolve?

I've always wondered how toxins in certain organisms have evolved. Particularly, organisms that produce toxins as a deterrent to predators as opposed to organisms that use it to paralyze their prey. ...
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1answer
76 views

How did people's liking of ceremonies evolve? [closed]

Habitual group activities are prevalent across many animal species, particularly in mammals, especially in primates. However, I do not see any evolutionary benefit of this. 'Ceremonies' take time, ...
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1answer
79 views

Extinction of species with extant descendants

From what I've seen, species such as Homo heidelbergensis which have extant descendants are classified as extinct, which makes sense as far as it goes. However, given that species exhibit a continuum ...
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Endothermy in different species

Birds and mammals are both endothermic, meaning they metabolically generate the heat they need to keep their body within a certain temperature ranger. But birds are closer relatives to reptiles than ...
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Is our genome decaying (see “Genetic Entropy”), and, if so, is this evidence for our genome being “young”?

In the book Genetic Entropy & the Mystery of the Genome the author says that the genome cannot be old because the genome is "decaying". Decay is a very subjective term, but in this case he means ...
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History: Do evolutionary and ecological processes occur at the same timescales?

Classically, it was thought that evolutionary processes occurred at a much slower pace than demographic/ecological processes. Nobody, ever thought about incorporating both processes into the same ...
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1answer
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Is it “easier” for researchers to detect evolutionary ancestry than distance in the evolutionary tree?

I'm a researcher in another field who has wandered into a problem with applications to biology. I hope to sell my results by making the following statement: Given two species X and Y, it is ...
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104 views

What was the evolutionary reason for cross lateralization of the brain?

In the human brain the right hemisphere controls the left side of the body and the left hemisphere controls the right side of the body. What led to this development? Why doesn't the left side of the ...
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Why does our body exhibit bilateral symmetry? [duplicate]

Externally, we (humans) look symmetrical. However, internal organs don't show the same patterns of symmetry (heart being on the left side while the liver is on the right side, etc.). It is a bit ...
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1answer
231 views

Did modern alligators and caimans come from prehistoric crocodiles?

I know that crocodilians have been here since the time of the dinosaurs. I also know that crocodiles came first. But alligators have been here for a good 37 million years. Did alligators come from ...
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Variance in Fst in the infinite island model

The most famous result in the study of structured populations come from Sewall Wright. He showed that in an island model, where each subpopulation is of size $N$ and the migration rate is $m$, then ...
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Is Mutation Theory still “valid” for complex organisms?

I'm afraid like most people I suffer from having learned "A History of Evolution" in school, rather than cutting to the chase and learning the actual "up to date" version of the subject. (Imagine if ...
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63 views

How did evolution support sports, fun, entertainment etc [duplicate]

We know that many animals entertain themselves by playing games. But sports actually increases risks of death,or at least accidents. So why did evolution choose it? And why did evolution decide to ...
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4answers
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Why would a plant evolve to produce an addictive chemical?

It seems kind of anti-productive in terms of survival for a plant to produce an addictive chemical as that plant will constantly be sought after by animals that ingest it. In this instance, I'm ...
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Evolution of protein and protein efficiency

Suppose we have a bacterial protein that performs a function and let's say we can measure the efficiency of the protein. Let's say we have two species, species A and B, both of which have this ...
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What are the evidence that all life today descended from a common ancestor (LUCA), and which organisms (if any) challenge the concept?

If I understand correctly, the concept of the LUCA (last universal common ancestor) is based on the hypothesis that archaea and bacteria share common ancestry. In the realm of mathematics, the same ...
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Why are lions the only social cats?

We know that almost all cats are solitary. How did the Lions (Panthera leo) end up social animals? Do we have an explanatory evolutionary path describing how the Lions became social while the rest of ...
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Within and Between Allelic Class Diversity

I am reading Charlesworth et al. 1997. They talk about diversity within and between allelic classes. Nucleotide diversities ($π$) at each neutral site were estimated from the mean of $2 \sum z_t ...
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1answer
175 views

Why does the number of mutations per individuals follow a Poisson distribution?

I was reading this review. On page 11, left column, first paragraph, one can read: [..] there is a Poisson distribution of the equilibrium number of mutations per individual, if fitness effects ...
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Driving force for speciation for millions of species today

I would like to know if speciation really occurs (trans-speciation). Have we had enough time for millions of species? A creationist argument is that the slow changes in traits in organisms, taking ...
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1answer
866 views

Why is the pituitary gland located in the brain?

Why is the pituitary gland located in the brain in humans, instead of elsewhere in the body? Why would this be an evolutionary beneficial adaptation?
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1answer
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Is there a schema for how human behavior is genetically determined?

It seem one can distinguish three different kinds of genetic determinism of common patterns of human behavior: behavior that is directly wired into our nervous system, e.g. face-related mirror ...
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What is variation in Speciation

I read a lot about speciation. To my knowledge, A species is often defined as a group of individuals that actually or potentially interbreed in nature and produce fertile offspring. Speciation is a ...
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135 views

Why are sight and sound prerequisites for intelligence?

Edward O. Wilson, in The Diversity of Life wrote (emphasis mine): Ninety-nine percent of the animals find their way by chemical trails. […] Animals are masters of this chemical channel, ...
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3answers
2k views

There aren't any animals like hornets that hunt large prey (like a rabbit, or even up to a deer), right? Why not?

There aren't any eusocial animals (hives of wasps, ants, termites, etc) that hunt large prey, are there? I'm thinking prey in the size range of, say, a rabbit, or even a deer. I can't see a rabbit ...
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Why are there no complex hermaphrodite land animals? [closed]

The title says it all. I know that 'complex' is a pretty ambiguous term to use, but I can't think of a more scientific term/definition for my meaning. I can't think of any large (larger then a small ...